Funny you would make a thread for this since it's already known that BLMs were called by name for buffs in 4.2, potency increases and decreased cast times for some spells, such as Fire, I assume you missed it.

As far as I know, GCD is still going to be ~2.5 seconds, but cast times themselves are apparently going to be around 1.5 - 2 seconds, giving you time to re-position yourself between casts, as well as make weaving OGCDs easier.